There was a time when 'good chemistry' meant converting coal tar into colorful and valuable dyes. Now good chemistry means that two people are comfortable and happy together.
Isn't it interesting how language evolves? Various disciplines toil away creating jargons with which to communicate their interesting news. Then all of a sudden a term is transported into general usage, the meaning changes, and seemingly clarity of communication is diminished for everyone. And yet the process works, the English language is effective and expressive and seems to evolve efficiently with time.
It is possible that the new use of the term 'good chemistry' stems from a widespread and abiding appreciation of the molecular nature of the endocrine system, neurotransmitters, and pheromones. However, it is also possible that 'good chemistry' is an echo of a memory, that somewhere in a forgotten classroom, two solutions when mixed, mysteriously yielded a new and valuable compound, somehow better than either parent solution. A metaphorical something for nothing is the new general theme that the phrase 'good chemistry' evokes.
The same strange distortion has occurred for the 'quantum leap', which in English means a monumental change, but in physics means one of the smallest changes possible. And, in recent years, the field of accountancy has undergone progressively greater degrees of stress as the term 'asset' has been applied ever more loosely, by English speakers everywhere, including the silver tongued variety on Wall Street. And now of course the term is combined with the word 'toxic', as if somehow the transferred jargon can divert us from the older term 'liability'.
In every field, the English language takes in meaningful jargon, chops the phrases around, without malice and with scant domain knowledge, and then regurgitates sometimes popular expressions. Fortunately, for journalists, accountants, chemists, engineers, and computer scientists, the strangely jarring but widely understood terms do not stay in common usage indefinitely.
Then there are terms which are not changed but have somewhat vaguer interpretations after they are transferred from jargon to general usage.
Molecule, for example, is a term which has a distinct meaning in science. However, in general usage it means either something which is small but visible, such as the last remaining fragment of a pair socks, something which happens to be in a scientific environment, or its normal scientific meaning. Of course, scientists are all too eager to draw pictures of molecules and therefore foster the illusion that molecules can be seen.
And every now and again a molecule makes its presence felt on the front page of the newspapers. Recently for example, astronomers detected naphthalene in the interstellar medium. This is not that surprising. Meteorites, for example, have long been known to contain carbon, much of it in forms not unlike naphthalene. So, if meteorites are formed from interstellar material which does not make it to the stars or planets, then presumably that medium contains carbon rich compounds like naphthalene. The triumph of the astronomers was to be able to determine unambiguously that naphthalene was present between the stars.
However, the news sources that picked up the naphthalene story focused on the complexity of naphthalene as a molecule, and the possibility that naphthalene might be a stepping stone towards the creation of the molecules from which primitive life could be constructed.
That certainly made for interesting headlines. It was only a matter of time before the headline 'Mothball Molecules in Outer Space' appeared. Perhaps the astronomers should have used the term spectroscopy more in the description of their work. Spectroscopy is a term which has not been transferred into general usage and so maintains a precise meaning. Of course, interstellar spectroscopy would make for duller headlines and probably no recognition for the astronomers outside their rarified ranks.
So perhaps the process of jargon transference and meaning dilution is a good thing. Jargon transference keeps the English language dynamic and adjusted to the concerns of the day. Additionally, it helps with transferring knowledge from jargon filled backwaters to general usage. Naturally this knowledge transfer mechanism is not as thorough as years spent in university lectures but in practice it serves the purpose of efficiently informing the language and keeping the specialists intelligible to the public.